It is often useful to determine and track position and orientation of platforms such as excavator platforms. As used herein, an excavator refers broadly to any type of construction equipment that includes a rotating platform. The rotating platform generally sits atop an undercarriage that includes tracks or wheels. Some types of construction equipment include a bucket or other implement that is coupled to the rotating platform. Both the position and orientation of the platform may be needed, for example, to determine a location of the bucket or other implement in space. This information is useful, for example, during digging processes.
Conventional techniques for determining position and orientation capture a number of position measurements during rotation of the platform and use curve fitting to fit an arc to the measurements. These conventional techniques often require the platform to rotate by up to 100° or more to provide a good curve for fitting. As an example, assuming a position measurement rate of 10 Hz, a swing of approximately 100° over a 4 second time period provides 40 data points for the curve fitting. Once the position and orientation are known, smaller changes can be tracked without requiring large swings of the platform. When the platform is moved from one location to another, however, an initialization process requiring large rotations must be repeated to determine the position and orientation at the new location.
In light of the above, improved methods for determining position and orientation of rotating platforms are desired.